Looks like courting to me, like he's trying to lock. You can see his tail is just alongside hers, not up and under (their vents are not in direct contact). Very promising though!
good luck
I don’t think I’d count it yet but it looks promising. I had a pair just like that and I wasn’t sure if I should count it as a lock either but the next time I paired them they had 100% Locked. I’d say once they are obviously not locked separate the male for a week and then reintroduce, once you witness a for sure Lock I like to only pair them for a couple days a month. But if I don’t see a 100% Lock I reintroduce weekly until I see one. This method has worked very well for me. I’ve got every pair to lock for me this season but one young male that may not be ready yet. Good luck!